Effector-triggered defence: A new concept in plant pathogen defence

In June, a team of Brassica researchers from the University of Hertfordshire proposed a new classification for a type of plant defence mechanism: effector-triggered defence (ETD).

Henrik Stotz is first author of the paper describing ETD, currently In Press in Trends in Plant Science. He explains, “In the same way that humans have developed immune responses against human disease pathogens, crops can be bred for resistance against disease pathogens, but we need to improve our understanding of effective resistance mechanisms within plants. Our research enhances the traditional understanding of the plant defence system and describes a new concept, which is how plants protect themselves against the pathogens that grow in the space outside plant cells (the apoplast) – a new concept called effector-triggered defence or ETD.”

Traditionally, plant pathogen defence is broken into two broad forms: pathogen-triggered immunity (PTI) and effector-triggered immunity (ETI). PTI is the first action the plant takes against a pathogen and is triggered when the pathogen lands on the plant. The pathogen releases molecules called effectors into the plant cells, which the plant recognises and reacts against. If the effectors are not recognised, the pathogen can spread with little resistance.

The team from Hertfordshire, led by Bruce Fitt, argue that one line of defence, R gene-mediated host resistance against fungal pathogens that grow in the space between cells, is not adequately explained by either mechanism.

Effector-triggered defence (ETD) is mediated by R genes encoding cell surface-bound receptor-like proteins that engage the receptor-like kinase SOBIR1 – an extracellular recognition. The response is host cell death after an extended period of endophytic pathogen growth. This is in contrast to ETI, in which detection of the pathogen occurs within cells and usually triggers fast host cell death.

This Arabidopsis Research Roundup has five papers that includes two from the John Innes Centre and two from the University of Edinburgh. Firstly Kristen Bomblies’s group at the JIC have investigated the relationship between temperature and meiotic recombination rates. Secondly Veronica Grieneisen and Stan Maree have developed a mathematical model to characterise cell morphologies taken[…]

The first two papers in this weeks Arabidopsis Research Roundup investigate different aspects of the plants response to temperature fluctuations. Firstly Lars Ostergaard (JIC) looks at the influence of temperature in the control of fruit dehiscence whilst Phil Wigge (SLCU) investigates crosstalk between chloroplast and nuclear signaling. The third paper from Ian Henderson (University of[…]

Charles Melnyk discusses a new paper published in PNAS that describes the molecular events that occur during grafting. The paper is entitled ‘Transcriptome dynamics at Arabidopsis graft junctions reveal an intertissue recognition mechanism that activates vascular regeneration‘ http://blog.garnetcommunity.org.uk/wp-content/uploads/2018/03/Melynk_180301.mp3Podcast: Play in new window | DownloadSubscribe: iTunes | Android | RSS

This edition of the Arabidopsis Research roundup beings with a study from SLCU that provides a molecular context to the changes that occur at graft junctions. Second is a study from Edinburgh that reports on the findings of a citizen science plant phenotyping project. Third are two studies from the John Innes Centre that follow-on[…]

This weeks Arabidopsis Research Roundup begins with a study from SLCU that investigates the interaction between nitrate and cytokinin signaling in the shoot meristem. Next is research from Sheffield that studies changes to the macromolecular composition of the photosynthetic apparatus following the transition from dark to light. Third are three papers that include University of[…]

GARNet with support from the Bristol Centre for Agricultural Innovation and New Phytologist are organising a Gene Editing Workshop that will take place at the University of Bristol on March 26th-27th 2018. This workshop is designed to encourage interactions and discussion about the use of CRISPR-Cas9 gene editing in plant systems. We are encouraging ECRs[…]

The cellular mechanics of auxin perception and signaling have been well studied over the past two decades. The pivotal interaction that controls this activity involves the auxin-dependent contact between the TIR1 receptor and a family of transcriptional regulators called AuxIAA proteins. This interaction has been characterised at a structural level with the auxin indole-3-acetic acid[…]

This weeks Arabidopsis Research Roundup begins with two papers from Royal Hollaway University of London that investigate the factors that control leaf development in the dark and the control of PIN1 phosphorylation. Third is a paper from Bristol that demonstrates the translation of research from Arabidopsis into coriander with regard the control of the response[…]

Enrique Lopez-Juez (Royal Holloway University of London) introduces a paper from that attempts to answer a critical question in plant science ‘Why do plants makes leaves in the dark‘? http://www.plantphysiol.org/content/early/2017/12/28/pp.17.01730.long http://blog.garnetcommunity.org.uk/wp-content/uploads/2018/01/Lopez_180116.mp3Podcast: Play in new window | DownloadSubscribe: iTunes | Android | RSS